Enterococcus wangshanyuanii sp. nov., isolated from faeces of yaks (Bos grunniens).

The taxonomic position of four phenotypically closely related strains isolated from faecal samples of yaks (Bos grunniens) collected from the Qinghai-Tibetan plateau, China, was determined by a polyphasic approach. The strains were non-spore-forming, non-motile Gram-stain-positive, ovoid cocci, occurring predominantly in pairs and short chains or in irregular clusters. The 16S rRNA gene of strain MN05T was related phylogenetically to those of Enterococcushaemoperoxidus, Enterococcusrotai, Enterococcusquebecensis, Enterococcusplantarum, Enterococcuscrotali, Enterococcusmoraviensis, Enterococcussilesiacus, Enterococcuscaccae, Enterococcustermitis, Enterococcusureasiticus and Enterococcusureilyticus, all belonging to the Enterococcusfaecalis species group. The sequence similarities of three selected genes of MN05T to those of the type strains of phylogenetically related species were measured, with values within the range of 99.2-99.5 % (16S rRNA gene), 90.0-97.3 % (rpoA) and 80.0-85.3 % (pheS), respectively. The genome of MN05T (3 842 361 bp) contained 4299 genes with a DNA G+C content of 37.5 mol%. A whole-genome phylogenetic tree based on 808 core genes confirmed that MN05T belongs to a distinct lineage, well separated from all recognized species of the Enterococcusfaecalis species group. DNA-DNA hybridization in silico showed that MN05T displayed less than 70 % DNA-DNA relatedness with the other 13 species of the Enterococcusfaecalis species group. Moreover, their phenotypic features distinguished the four strains from the other species of the Enterococcusfaecalis species group. Based upon these data obtained from the polyphasic characterization performed in the present study, a novel species of the genus Enterococcus, Enterococcus wangshanyuanii sp. nov., is proposed, with the type strain MN05T (=DSM 104047T=CGMCC 1.15942T).

Actinomyces gaoshouyii sp. nov., isolated from plateau pika (Ochotona curzoniae).

Two strains (pika_113T and pika_114) of a previously undescribed Actinomyces-like bacterium were recovered from the intestinal contents of plateau pika (Ochotona curzoniae) on the Tibet-Qinghai Plateau, China. Results from biochemical characterization indicated that the two strains were phenotypically homogeneous and distinct from other previously described species of the genus Actinomyces. Based on the comparison of 16S rRNA gene sequences and genome analysis, the bacteria were determined to be a hitherto unknown subline within the genus Actinomyces, being most closely related to type strains of Actinomyces denticolens and Actinomyces timonensis with a respective 97.2 and 97.1 % similarity in their 16S rRNA gene sequences. Phylogenetic analyses confirmed that pika_113T was well separated from any other recognized species of the genus Actinomyces and within the cluster with A. denticolens and A. timonensis. The genome of strain pika_113T displayed less than 42 % relatedness in DNA-DNA hybridization with all the available genomes of existing species of the genus Actinomyces in the NCBI database. Collectively, based on the phenotypic characteristics and phylogenetic analyses results, we propose the novel isolates as representatives of Actinomyces gaoshouyii sp. nov. The type strain of Actinomyces gaoshouyii is pika_113T (=CGMCC 4.7372T=DSM 104049T), with a genomic DNA G+C content of 71 mol%.

Actinomyces liubingyangii sp. nov. isolated from the vulture Gypaetus barbatus.

Two strains (VUL4_1T and VUL4_2) of Gram-staining-positive, catalase-negative, non-spore-forming short rods were isolated from rectal swabs of Old World vultures (Gypaetus barbatus) in the Tibet-Qinghai Plateau, China. Analysis of morphological characteristics and biochemical tests indicated that the two strains closely resembled each other but were distinct from other species of the genus Actinomyces previously described. Based on the results of 16S rRNA gene sequence comparison and genome analysis, strains were determined to be members of the genus Actinomyces, closely related to the type strains of Actinomyces marimammalium (96.4 % 16S rRNA gene sequence similarity), Actinomyceshongkongensis (92.4 %), Actinomyceshordeovulneris (92.3 %) and Actinomycesnasicola (92.2 %), respectively. Optimal growth conditions were 37 °C, pH 6-7, with 1 % (w/v) NaCl. Strain VUL4_1T contained C18 : 1ω9c and C16 : 0 as the major cellular fatty acids and diphosphatidylglycerol as the major component of the polar lipids. The genomic DNA G+C content of VUL4_1T was 54.9 mol%. Strain VUL4_1T showed less than 70 % DNA-DNA relatedness with other species of the genus Actinomyces, further supporting strain VUL4_1T as a representative of a novel species. Based on the phenotypic data and phylogenetic inference, a novel species, Actinomyces liubingyangii sp. nov., is proposed with VUL4_1T (=CGMCC 4.7370T=DSM 104050T) as the type strain.

Screening and characterization of endophytic Bacillus and Paenibacillus strains from medicinal plant Lonicera japonica for use as potential plant growth promoters.

A total of 48 endophytic bacteria were isolated from surface-sterilized tissues of the medicinal plant Lonicera japonica, which is grown in eastern China; six strains were selected for further study based on their potential ability to promote plant growth in vitro (siderophore and indoleacetic acid production). The bacteria were characterized by phylogenetically analyzing their 16S rRNA gene similarity, by examining their effect on the mycelial development of pathogenic fungi, by testing their potential plant growth-promoting characteristics, and by measuring wheat growth parameters after inoculation. Results showed that the number of endophytic bacteria in L. japonica varied among different tissues, but it remained relatively stable in the same tissues from four different plantation locations. Among the three endophytic strains, strains 122 and 124 both had high siderophore production, with the latter showing the highest phosphate solubilization activity (45.6 mg/L) and aminocyclopropane-1-carboxylic acid deaminase activity (47.3 nmol/mg/h). Strain 170 had the highest indoleacetic acid (IAA) production (49.2 mg/L) and cellulase and pectinase activities. After inoculation, most of the six selected isolates showed a strong capacity to promote wheat growth. Compared with the controls, the increase in the shoot length, root length, fresh weight, dry weight, and chlorophyll content was most remarkable in wheat seedlings inoculated with strain 130. The positive correlation between enzyme (cellulose and pectinase) activity and inhibition rate on Fusarium oxysporum, the IAA production, and the root length of wheat seedlings inoculated with each tested endophytic strain was significant in regression analysis. Deformity of pathogenic fungal mycelia was observed under a microscope after the interaction with the endophytic isolates. Such deformity may be directly related to the production of hydrolytic bacterial enzymes (cellulose and pectinase). The six endophytic bacterial strains were identified to be Paenibacillus and Bacillus strains based on the results of 16S rRNA gene sequencing analysis and their physiological and biochemical characteristics. Results indicate the promising application of endophytic bacteria to the biological control of pathogenic fungi and the improvement of wheat crop growth.

Screening and characterization of endophytic Bacillus and Paenibacillus strains from medicinal plant Lonicera japonica for use as potential plant growth promoters

Abstract A total of 48 endophytic bacteria were isolated from surface-sterilized tissues of the medicinal plant Lonicera japonica, which is grown in eastern China; six strains were selected for further study based on their potential ability to promote plant growth in vitro (siderophore and indoleacetic acid production). The bacteria were characterized by phylogenetically analyzing their 16S rRNA gene similarity, by examining their effect on the mycelial development of pathogenic fungi, by testing their potential plant growth-promoting characteristics, and by measuring wheat growth parameters after inoculation. Results showed that the number of endophytic bacteria in L. japonica varied among different tissues, but it remained relatively stable in the same tissues from four different plantation locations. Among the three endophytic strains, strains 122 and 124 both had high siderophore production, with the latter showing the highest phosphate solubilization activity (45.6 mg/L) and aminocyclopropane-1-carboxylic acid deaminase activity (47.3 nmol/mg/h). Strain 170 had the highest indoleacetic acid (IAA) production (49.2 mg/L) and cellulase and pectinase activities. After inoculation, most of the six selected isolates showed a strong capacity to promote wheat growth. Compared with the controls, the increase in the shoot length, root length, fresh weight, dry weight, and chlorophyll content was most remarkable in wheat seedlings inoculated with strain 130. The positive correlation between enzyme (cellulose and pectinase) activity and inhibition rate on Fusarium oxysporum, the IAA production, and the root length of wheat seedlings inoculated with each tested endophytic strain was significant in regression analysis. Deformity of pathogenic fungal mycelia was observed under a microscope after the interaction with the endophytic isolates. Such deformity may be directly related to the production of hydrolytic bacterial enzymes (cellulose and pectinase). The six endophytic bacterial strains were identified to be Paenibacillus and Bacillus strains based on the results of 16S rRNA gene sequencing analysis and their physiological and biochemical characteristics. Results indicate the promising application of endophytic bacteria to the biological control of pathogenic fungi and the improvement of wheat crop growth.